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"GALAPAGOS-C" : Analysis of Galaxy Morphologies Using High Performance Computing Methods / Andreas Hiemer
VerfasserHiemer, Andreas
GutachterSchindler, Sabine
UmfangXVIII, 188 Bl. : Ill., graph. Darst., Kt.
HochschulschriftInnsbruck, Univ., Diss., 2014
Datum der AbgabeNovember 2014
Bibl. ReferenzOeBB
Schlagwörter (DE)Galaxien / Galaxienhaufen / Galaxien: Asymmetrie / Galaxien: Morphologie / Galaxien: Struktur / Galaxien: Stukturanalyse / Galaxien: Entwicklung
Schlagwörter (GND)Galaxienhaufen / Harmonische Analyse / Weltraumteleskop
URNurn:nbn:at:at-ubi:1-1786 Persistent Identifier (URN)
 Das Werk ist frei verfügbar
"GALAPAGOS-C" [9.09 mb]
Zusammenfassung ([engl.])

Modern imaging surveys provide a fundamental tool in order to study the morphological properties of galaxy populations in the nearby and the distant Universe. In order to process a complete set of survey images, we designed GALAPAGOS-C. GALAPAGOS-C unifies the detection of sources (via source extractor), postage stamp cutting, object mask preparation, sky background estimation and complex two-dimensional light profile Sérsic modelling (via GALFIT) in one automatic program. GALAPAGOS-C is designed around the concept of MPI-parallelization, allowing the processing of large data sets in a quick and efficient manner. Further, galapagos-c is capable of fitting multiple Sérsic profiles to each galaxy, each representing distinct galaxy components (e.g. bulge, disc, bar), in addition to the option to fit asymmetric distortions with a Fourier mode expansion to the axis-symmetric single-Sérsic isophotes. The modelling reliability of our core single-Sérsic fitting capability and the optional Fourier mode expansion are tested thoroughly using image simulations.GALAPAGOS-C is applied to a sample of 2063 galaxies in the A901/902 galaxy cluster (z 0.165) from the Space Telescope A901/902 Galaxy Evolution Survey (STAGES) and an additional sample of 2876 field galaxies from the Galaxy Evolution From Morphology And SEDs Survey (GEMS). We measure the distribution of Sérsic indices as a function of local object density in the A901/902 cluster sample to provide one of the first measures of the Sérsic indexdensity relation. In addition, we measure the distribution of lopsided galaxies in the A901/902 cluster sample and quantify the intensity of lopsidedness in the galaxies in the field since z 0.9 in order to study the evolution of lopsidedness as a function of redshift. In each application, we study the correlations of the measured parameters with other intrinsic and structural variables, e.g. the stellar mass, the color or the presence or absence of a disk. Our results provide further clues on the evolution of galaxy structure with cosmic time and the dependence on environment.